How to find tdc
10-17-2006, 08:51 PM
#2
Registered User
Join Date: Sep 2006
Location: Gainesville, Ga
Posts: 501
Likes: 0
Received 0 Likes
on
0 Posts
Logan...
There is only one way to find TDC on any engine and be precise. The problem is that when the piston is at TDC the crank is still rotating and the piston is not moving, so indicators do not work. I have used the following method for more years than I hate to admit and it is the only real way to be exact or nearly so.
You will need a degree wheel mounted to the front of the crank with a pointer. Remove #1 injector or glow plug, something that will give you a threaded hole into the top of the cylinder. With a bolt or stop threaded into the hole deep enough to contact the piston, rotate the crank by hand very slowly until you feel the piston make very light contact on the inserted stop.
Read the degree wheel, maybe even loosen and rotate so the pointer is on zero. Now, rotate the crank by hand slowly in the opposite direction until you feel the piston gently bump the stop. Look at the degree wheel. If you set it on zero and then rotated it the opposite direction and it stopped on 15 degrees, split the difference in two (7 1/2 degrees) and that is your actual TDC. Make sure that you are doing this on the compression stroke
I hope this is what you were looking for. Good luck
There is only one way to find TDC on any engine and be precise. The problem is that when the piston is at TDC the crank is still rotating and the piston is not moving, so indicators do not work. I have used the following method for more years than I hate to admit and it is the only real way to be exact or nearly so.
You will need a degree wheel mounted to the front of the crank with a pointer. Remove #1 injector or glow plug, something that will give you a threaded hole into the top of the cylinder. With a bolt or stop threaded into the hole deep enough to contact the piston, rotate the crank by hand very slowly until you feel the piston make very light contact on the inserted stop.
Read the degree wheel, maybe even loosen and rotate so the pointer is on zero. Now, rotate the crank by hand slowly in the opposite direction until you feel the piston gently bump the stop. Look at the degree wheel. If you set it on zero and then rotated it the opposite direction and it stopped on 15 degrees, split the difference in two (7 1/2 degrees) and that is your actual TDC. Make sure that you are doing this on the compression stroke
I hope this is what you were looking for. Good luck
10-17-2006, 09:39 PM
#3
Registered User
Join Date: Jan 2002
Location: Southern, Indiana
Posts: 5,352
Likes: 0
Received 0 Likes
on
0 Posts
I just use the TDC mark on the damper.
If you can feel open lash on the #1 intake and #1 exhaust then the motor is @ TDC. If you have the TDC mark on the crank in the TDC location and both of the valves listed above are in compressed positions then the engine is @ 180* out.
This method works.....
If you can feel open lash on the #1 intake and #1 exhaust then the motor is @ TDC. If you have the TDC mark on the crank in the TDC location and both of the valves listed above are in compressed positions then the engine is @ 180* out.
This method works.....
10-17-2006, 11:09 PM
#4
Registered User
Join Date: Sep 2006
Location: Oklahoma
Posts: 911
Likes: 0
Received 0 Likes
on
0 Posts
this method will work on any motor. including two stroke chainsaws with no TDC markings.
Logan...
There is only one way to find TDC on any engine and be precise. The problem is that when the piston is at TDC the crank is still rotating and the piston is not moving, so indicators do not work. I have used the following method for more years than I hate to admit and it is the only real way to be exact or nearly so.
You will need a degree wheel mounted to the front of the crank with a pointer. Remove #1 injector or glow plug, something that will give you a threaded hole into the top of the cylinder. With a bolt or stop threaded into the hole deep enough to contact the piston, rotate the crank by hand very slowly until you feel the piston make very light contact on the inserted stop.
Read the degree wheel, maybe even loosen and rotate so the pointer is on zero. Now, rotate the crank by hand slowly in the opposite direction until you feel the piston gently bump the stop. Look at the degree wheel. If you set it on zero and then rotated it the opposite direction and it stopped on 15 degrees, split the difference in two (7 1/2 degrees) and that is your actual TDC. Make sure that you are doing this on the compression stroke
I hope this is what you were looking for. Good luck
There is only one way to find TDC on any engine and be precise. The problem is that when the piston is at TDC the crank is still rotating and the piston is not moving, so indicators do not work. I have used the following method for more years than I hate to admit and it is the only real way to be exact or nearly so.
You will need a degree wheel mounted to the front of the crank with a pointer. Remove #1 injector or glow plug, something that will give you a threaded hole into the top of the cylinder. With a bolt or stop threaded into the hole deep enough to contact the piston, rotate the crank by hand very slowly until you feel the piston make very light contact on the inserted stop.
Read the degree wheel, maybe even loosen and rotate so the pointer is on zero. Now, rotate the crank by hand slowly in the opposite direction until you feel the piston gently bump the stop. Look at the degree wheel. If you set it on zero and then rotated it the opposite direction and it stopped on 15 degrees, split the difference in two (7 1/2 degrees) and that is your actual TDC. Make sure that you are doing this on the compression stroke
I hope this is what you were looking for. Good luck
Thread
Thread Starter
Forum
Replies
Last Post
92smokin blacky
1st Gen. Ram - All Topics
18
03-10-2011 09:30 AM
05Supersomker
3rd Gen Engine and Drivetrain -> 2003-2007
4
12-19-2007 09:34 PM
1980240D
3rd Gen Engine and Drivetrain -> 2003-2007
3
11-25-2007 10:57 AM
1320
12 Valve Engine and Drivetrain
11
04-27-2004 11:53 AM